1. Field of the Invention
The present invention pertains generally to devices and methods for smoothing or working concrete and cement, and more particularly to a lightweight concrete screed with a removable and interchangeable screeding edge for providing a smooth finish to concrete and the like.
2. Description of the Background Art
Smoothing or leveling of concrete surfaces is frequently required in the construction of residential, commercial, and other types of buildings and structures. A concrete screed is generally used for screeding freshly poured concrete to provide smooth and level surfaces for floors and the like. Frequently, a simple piece of lumber with a smooth surface, such as a "2 by 4", is employed as a screed, and is drawn or pulled across a wet concrete surface by one or more persons in order to level the surface. Concrete screeding is a difficult and labor-intensive operation which must be carried out quickly before the poured concrete sets up, and once the concrete has hardened, errors or defects in the concrete surfaces generally cannot be corrected.
To facilitate concrete screeding, a variety of screed devices have been developed. For example, U.S. Pat. No. 5,324,085 discloses a concrete screed handle assembly wherein a U-shaped tubular bar contains clamping points which accommodate a screed board. U.S. Pat. No. 4,702,641 discloses a multi-purpose concrete working tool having a long blade with sharp edges coupled to a handle and lateral braces. U.S. Pat. No. 4,641,995 discloses a user-mounted concrete screed in which a screed plate with a vibrator is harnessed to an operator. U.S. Pat. No. 4,449,845 discloses a screed board apparatus wherein a screed board is harnessed to an operator and controlled by handles. U.S. Pat. No. 2,306,671 discloses a concrete screed and guide in which a smoothing blade is slidably mounted on runners. U.S. Pat. No. 1,929,660 discloses a method of making a road tool which employs an elongated smooth body joined to a handle. U.S. Pat. No. 1,887,195 discloses a means for surfacing sand and the like wherein a bar is supported between two rolling supports. U.S. Pat. No. 1,586,325 discloses a device for smoothing the surface of concrete pavements in which a platform or float is drawn across concrete surfaces by a wheeled carrier.
As can be seen therefore, several concrete smoothing or leveling devices are known. However, a number of deficiencies are present in these conventional devices. For example, such devices are generally heavy and tiresome to operate. Particularly, wooden screed boards are heavy and cumbersome, and devices for holding screed boards do not alleviate the weight of such boards. Efforts to provide screeding devices of reduced weight have tended to rely on thin, blade-like screeds which can warp or twist during use, making the screeds difficult to use and resulting in uneven concrete surfaces. Another drawback experienced in many devices is that the screed surface, which becomes abraded and worn during repeated use with rough concrete, is difficult to replace or cannot be replaced at all. Ultimately, the screed surface may become so worn that it can no longer provide smooth surfaces to concrete, and the entire screed must be discarded.
Thus, there is a need for a concrete screed which is lightweight and easy to use, which is rigid and durable and does not bend or warp during use, and which has an easily replaceable screed surface. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in the background art.
The foregoing patents reflect the state of the art of which the applicant is aware and are tendered with the view toward discharging applicant's acknowledged duty of candor in disclosing information which may be pertinent in the examination of this application. It is respectfully stipulated, however, that none of these patents teach or render obvious, singly or when considered in combination, applicant's claimed invention.